Hi all,
I would like to know if I could share some space on on of my servers, to another server(s) using the iSCSI protocal? I can see that CentOS can connect to an iSCSI server, but can it act as a iSCSI server?
Is so, does anyone have some good HOWTO / tutorials / docs on how to set it up?
I'm running CentOS 5.2
Rudi Ahlers wrote:
Hi all,
I would like to know if I could share some space on on of my servers, to another server(s) using the iSCSI protocal? I can see that CentOS can connect to an iSCSI server, but can it act as a iSCSI server?
Is so, does anyone have some good HOWTO / tutorials / docs on how to set it up?
I'm running CentOS 5.2
Yes you can , but actually it's still 'techonology preview' as stated in the Upstream Release Notes ... You'll need to install the package scsi-target-utils and configure everything with the tgtadm command : there is no config file that is read by the /etc/rc.d/init.d/tgtd initscripts so you have to write a bash scripts that will be read on startup to do the whole work. If you have already played with iscsi, using tgtadm is not really difficult but i admit also that i'm only using it for tests in labs. Production machines are using FC HBAs ;-)
On Sun, Nov 16, 2008 at 5:00 PM, Fabian Arrotin fabian.arrotin@arrfab.net wrote:
Rudi Ahlers wrote:
Hi all,
I would like to know if I could share some space on on of my servers, to another server(s) using the iSCSI protocal? I can see that CentOS can connect to an iSCSI server, but can it act as a iSCSI server?
Is so, does anyone have some good HOWTO / tutorials / docs on how to set it up?
I'm running CentOS 5.2
Yes you can , but actually it's still 'techonology preview' as stated in the Upstream Release Notes ... You'll need to install the package scsi-target-utils and configure everything with the tgtadm command : there is no config file that is read by the /etc/rc.d/init.d/tgtd initscripts so you have to write a bash scripts that will be read on startup to do the whole work. If you have already played with iscsi, using tgtadm is not really difficult but i admit also that i'm only using it for tests in labs. Production machines are using FC HBAs ;-) --
Fabian Arrotin fabian.arrotin@arrfab.net "Internet network currently down, TCP/IP packets delivered now by UPS/Fedex ..."
Hi Fabian,
Do you have any documentation for me on this? I don't know iSCSI at all - well I haven't used it before myself, but from what I understand it's much better than NFS.
What is FC HBA's ?
Rudi Ahlers wrote:
On Sun, Nov 16, 2008 at 5:00 PM, Fabian Arrotin fabian.arrotin@arrfab.net wrote:
Rudi Ahlers wrote:
<snip>
Hi Fabian,
Do you have any documentation for me on this? I don't know iSCSI at all - well I haven't used it before myself, but from what I understand it's much better than NFS.
Consider then reading http://en.wikipedia.org/wiki/Iscsi your homework .. ;-) Don't try to compare NFS and iScsi : they aren't working at the same level : iScsi works at the 'block level' while other Network File Systems (like NFS, CIFS, etc ...) work more at the 'file level' . So they are serving different needs. While multiple hosts can access directly a NFS exported fs, iscsi share a block device (target) to an initiator host (or multiple hosts). Except if you're using a cluster FS like GFS, you can't access the same lun from multiple initiators at the same time
What is FC HBA's ?
Fiber Channel Host Bus Adapters ;-)
Fabian Arrotin wrote:
Don't try to compare NFS and iScsi : they aren't working at the same level : iScsi works at the 'block level' while other Network File Systems (like NFS, CIFS, etc ...) work more at the 'file level'
Hmmm. CIFS works at block level (SMB == Server Message Blocks). iSCSI is a transport protocol while CIFS and/or NFS a file systems :)
Ralph
On Nov 17, 2008, at 5:36 AM, Ralph Angenendt ra+centos@br-online.de wrote:
Fabian Arrotin wrote:
Don't try to compare NFS and iScsi : they aren't working at the same level : iScsi works at the 'block level' while other Network File Systems (like NFS, CIFS, etc ...) work more at the 'file level'
Hmmm. CIFS works at block level (SMB == Server Message Blocks). iSCSI is a transport protocol while CIFS and/or NFS a file systems :)
SMB despite it's name does not work on the block level, but the file system level.
CIFS/NFS are ways of extending the file system across the network.
iSCSI is a way of extending the disk drive or array over the network. It's a subtle by important difference.
-Ross
See my presentation at http://www.colug.net/notes/0810mtg/
On Sun, 16 Nov 2008, Rudi Ahlers wrote:
Hi all,
I would like to know if I could share some space on on of my servers, to another server(s) using the iSCSI protocal? I can see that CentOS can connect to an iSCSI server, but can it act as a iSCSI server?
Is so, does anyone have some good HOWTO / tutorials / docs on how to set it up?
I'm running CentOS 5.2
---------------------------------------------------------------------- Jim Wildman, CISSP, RHCE jim@rossberry.com http://www.rossberry.com "Society in every state is a blessing, but Government, even in its best state, is a necessary evil; in its worst state, an intolerable one." Thomas Paine
On Nov 16, 2008, at 7:21 AM, "Rudi Ahlers" rudiahlers@gmail.com wrote:
Hi all,
I would like to know if I could share some space on on of my servers, to another server(s) using the iSCSI protocal? I can see that CentOS can connect to an iSCSI server, but can it act as a iSCSI server?
Is so, does anyone have some good HOWTO / tutorials / docs on how to set it up?
I'm running CentOS 5.2
There is also the iSCSI Enterprise Target besides the technology preview of 'tgt' which is more then just iSCSI, but a generic SCSI target that can also do FC and FCoE.
IET has a kernel device device driver though that will need to be maintained through kernel updates, but works extremely well.
-Ross
On Sun, 2008-11-16 at 19:28 -0500, Ross Walker wrote:
On Nov 16, 2008, at 7:21 AM, "Rudi Ahlers" rudiahlers@gmail.com wrote:
Hi all,
I would like to know if I could share some space on on of my servers, to another server(s) using the iSCSI protocal? I can see that CentOS can connect to an iSCSI server, but can it act as a iSCSI server?
Is so, does anyone have some good HOWTO / tutorials / docs on how to set it up?
I'm running CentOS 5.2
There is also the iSCSI Enterprise Target besides the technology preview of 'tgt' which is more then just iSCSI, but a generic SCSI target that can also do FC and FCoE.
IET has a kernel device device driver though that will need to be maintained through kernel updates, but works extremely well.
-Ross
+1 for this, setup is extremely simple and fast.
And there's builds @ http://atrpms.net/dist/el5/iscsitarget/ that work with CentOS 5.
-
Fabian Arrotin -
Jim Wildman -
Matthew Kent -
Ralph Angenendt -
Ross Walker -
Rudi Ahlers